Molecular breast imaging shows its supplemental chops as a routine-practice tool

Molecular breast imaging (MBI) has proven a useful secondary screening tool for women with dense breasts when routinely deployed at a large, community-based breast imaging center.

Researchers at ProMedica Breast Care in Toledo, Ohio, found that the technology yielded a high incremental cancer detection rate of 7.7 cancers per thousand, and at an acceptable radiation dose.

Robin Shermis, MD, and colleagues report their results in the August edition of the American Journal of Roentgenology.

The team retrospectively analyzed the cases of 1,696 women with dense breasts and negative mammography results who subsequently underwent screening with 99mTc-sestamibi molecular breast exams.

They found these exams had caught 13 malignancies that mammography had missed, including 11 that were invasive.

Along with the 7.7/1,000 incremental detection rate, the authors noted a recall rate of 8.4 percent and a biopsy rate of 3.7 percent.

The positive predictive value for recall (PPV 1) was 9.1 percent; for biopsy (PPV 3), it was 19.4 percent.

Lesion size ranged from 0.6 to 2.4 centimeters.

Along with the study’s single-institution parameters, the authors acknowledge as limitations possible selection bias owing to patient acceptance of the molecular exam and the technology’s availability to ProMedica’s radiologists.

Concluding that their study shows MBI detects additional cancers in women with dense breasts at an acceptable level of radiation exposure—300 MBq (8 mCi), corresponding to an effective radiation dose of 2.4 mSv—the authors point out that MBI is well tolerated and provides an alternative to MRI for claustrophobic or obese persons.

“Molecular breast imaging is relatively easy to perform and interpret and is associated with low biopsy rates, thus overcoming some of the major limitations of screening ultra-sound,” they write. “As such, molecular breast imaging is a suitable supplementary screening modality for women with dense breast tissue.”

The study amplifies findings from a prospective, blinded investigation reported in the same journal by Mayo Clinic researchers last year.

Earlier this month MBI vendor Gamma Medica publicized the present study, with additional information on the technology and the findings, in a press release.